Free radicals are molecules with an unpaired electron. That makes them unstable. To settle down, they steal an electron from a nearby molecule—which then becomes a free radical itself. Steal, repeat. That’s a self-perpetuating chain reaction: each step creates another radical, so the process doesn’t wind down on its own. It continues until it is physically stopped—either by an antioxidant stepping in to donate an electron and break the chain, or by a termination event (e.g. two radicals meeting and pairing up). Without one of those, the cascade keeps going.
What that does to your body
That “something” is often your own cells: lipids, proteins, DNA. The damage is called oxidative stress. Over time it’s linked to aging, inflammation, and a higher risk of many diseases. One bad actor can start a cascade.
How it stops
The reaction ends when:
- An antioxidant donates an electron and neutralizes the radical (without becoming dangerous itself), or
- Two radicals meet and pair up—a termination event.
Antioxidants (from food, or made in your body) are the main brake. They’re why “eat your greens” and “enough sleep” aren’t just folklore—they support your built-in repair crew.
One unstable molecule can multiply. Antioxidants are how you hit stop.